1. Field of the Invention
The present invention is directed to an antenna arrangement suited for conducting a magnetic resonance examination of a female breast.
2. Description of the Prior Art
A mammography antenna arrangement for magnetic resonance examinations of a female breast is disclosed in German OS 31 31 946, corresponding to U.S. Pat. No. 4,467,282. This known arrangement has first and second conductor loop pairs. Each pair is formed by two saddle-shaped conductor loops lying opposite one another and between which an essentially cylindrical examination space is located. The two conductor loop pairs are rotationally offset by 90.degree. relative to one another in a circumferential direction.
Magnetic resonance examinations with circularly polarized radio-frequency fields can be implemented with this antenna arrangement. That known arrangement has two conductor loop pairs offset by 90.degree. relative to one another with respective antenna characteristics residing perpendicularly to one another in the inside of the examination space surrounded by the conductor loop pairs, which are arranged on a cylindrical carrier member. The longitudinal axis of the antenna arrangement is directed parallel to the static basic magnetic field, as a result of which the radio-frequency fields generated during transmission and the most sensitive reception regions are disposed perpendicularly relative to the basic magnetic field. The antenna arrangement is dimensioned as a whole-body antenna; an entire human body can be introduced into the examination space in the axial direction through an acceptance opening. Antenna arrangements that are shorter in the axial direction, however, are desirable for examining sub-areas of the human body. In this known antenna, however, a shortening of the effective antenna conductors degrades the imaging properties.